param_binding_helpers.hh

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/*
 * param_binding_helpers.hh
 *
 *  Created on: Jan 23, 2020
 *      Author: N. Oblath, L. Gladstone, B.H. LaRoque
 */

#ifndef PARAM_BINDING_HELPERS_HH_
#define PARAM_BINDING_HELPERS_HH_

#include <algorithm> //for std::replace on string

#include "param.hh"
#include "error.hh"

#include "pybind11/pybind11.h"
#include "pybind11/pytypes.h"


namespace scarab_pybind
{

    scarab::param_ptr_t to_param( const pybind11::object& an_object, bool hyphenate_keys=false )
    {
        using namespace pybind11;
        if( isinstance< none >( an_object ) )
        {
            return scarab::param_ptr_t( new scarab::param() );
        }
        else if( isinstance< bool_ >( an_object ) )
        {
            return scarab::param_ptr_t( new scarab::param_value( static_cast< const bool_& >(an_object) ) );
        }
        else if( isinstance< int_ >( an_object ) )
        {
            return scarab::param_ptr_t( new scarab::param_value( (int64_t)static_cast< const int_& >(an_object) ) );
        }
        else if( isinstance< float_ >( an_object ) )
        {
            return scarab::param_ptr_t( new scarab::param_value( (double)static_cast< const float_& >(an_object) ) );
        }
        else if( isinstance< str >( an_object ) )
        {
            return scarab::param_ptr_t( new scarab::param_value( static_cast< const str& >(an_object) ) );
        }
        else if( isinstance< list >( an_object ) )
        {
            scarab::param_ptr_t the_return( new scarab::param_array() );
            scarab::param_array& the_return_arr = the_return->as_array();
            for( auto an_item = an_object.begin(); an_item != an_object.end(); ++an_item )
            {
                the_return_arr.push_back( to_param( reinterpret_borrow< object >( *an_item ) ) );
            }
            return the_return;
        }
        else if( isinstance< dict >( an_object ) )
        {
            scarab::param_ptr_t the_return( new scarab::param_node() );
            scarab::param_node& the_return_arr = the_return->as_node();
            const dict& a_dict = static_cast< const dict& >( an_object );
            for( auto an_item = a_dict.begin(); an_item != a_dict.end(); ++an_item )
            {
                if( ! isinstance< str >(an_item->first) || ! isinstance< object >(an_item->second) )
                {
                    throw scarab::error() << "Cannot convert dict to param";
                }
                std::string new_key = pybind11::str(an_item->first);
                if ( hyphenate_keys )
                {
                    std::replace( new_key.begin(), new_key.end(), '_', '-' );
                }
                the_return_arr.add( new_key, to_param( static_cast< const object& >(an_item->second) ) );
            }
            return the_return;
        }
        throw scarab::error() << "Unknown python type cannot be converted to param";
    };

    pybind11::object to_python( const scarab::param& a_param, bool underscore_keys = false )
    {
        if (a_param.is_null())
        {
            return pybind11::none();
        }
        else if (a_param.is_value())
        {
            const scarab::param_value& this_value = a_param.as_value();
            pybind11::object to_return;
            if (this_value.is_bool()) to_return =  pybind11::cast(this_value.as_bool());
            else if (this_value.is_uint()) to_return = pybind11::cast(this_value.as_uint());
            else if (this_value.is_int()) to_return = pybind11::cast(this_value.as_int());
            else if (this_value.is_double()) to_return = pybind11::cast(this_value.as_double());
            else if (this_value.is_string()) to_return = pybind11::cast(this_value.as_string());
            return to_return;
        }
        else if (a_param.is_array())
        {
            const scarab::param_array& this_array = a_param.as_array();
            pybind11::list to_return;
            for (scarab::param_array_const_iterator an_item=this_array.begin(); an_item != this_array.end(); ++an_item)
            {
                to_return.append( to_python( *an_item ) );
            }
            return std::move(to_return);
        }
        else if (a_param.is_node())
        {
            const scarab::param_node& this_node = a_param.as_node();
            pybind11::dict to_return;
            for (scarab::param_node_const_iterator an_item=this_node.begin(); an_item != this_node.end(); ++an_item)
            {
                std::string new_key = an_item.name();
                if ( underscore_keys )
                {
                    std::replace( new_key.begin(), new_key.end(), '-', '_' );
                }
                to_return[ new_key.c_str() ] = to_python( *an_item );
            }
            return std::move(to_return);
        }
        throw scarab::error() << "Unknown param type cannot be converted to Python";
    };

} /* namespace scarab_pybind */
#endif /* PARAM_BINDING_HLEPERS_HH_ */